Untitled Quiz

The Biological Approach

• The biological approach emphasizes the role of the brain, neurotransmitters, hormones, and genes in explaining behavior and mental processes.

Organization of the Nervous System

• The nervous system is organized into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS consists of the brain and spinal cord, whereas the PNS comprises all the nerves outside the CNS.
  • The PNS is then subdivided into the somatic nervous system and the autonomic nervous system.
    • The somatic nervous system controls voluntary movements.
    • The autonomic nervous system controls involuntary functions, like heart rate and digestion. It has two main branches: the sympathetic nervous system and the parasympathetic nervous system.
      • The sympathetic nervous system is associated with 'fight or flight' responses.
      • The parasympathetic nervous system is associated with 'rest and digest' responses.

Central Nervous System

• The central nervous system (CNS) comprises the brain and spinal cord.
• It is responsible for receiving, processing, and sending information throughout the body.

Peripheral Nervous System

• The peripheral nervous system (PNS) consists of all the nerves outside the brain and spinal cord.
• It is responsible for communicating information to and from the CNS.
• The somatic nervous system controls voluntary activities.
• The autonomic nervous system regulates involuntary actions.

Autonomic Nervous System

• All of the nerves in the peripheral nervous system that serve involuntary systems of the body.
• The autonomic nervous system is responsible for involuntary bodily processes.
• This system is divided into two sub-divisions: Sympathetic and Parasympathetic.

Sympathetic Nervous System

• Activates the body during emergency conditions.
• Responsible for 'fight or flight' responses.
• It diverts blood from the digestive systems, thus directing it towards muscles and lungs.

Parasympathetic Nervous System

• Calms the body down after a 'fight or flight' response.
• Responsible for 'rest and digest' responses.
• It diverts blood to digestive systems, slowing the heart rate.

Origins of Neuron Doctrine

• Humoral theory: The theory that the human body is comprised of 4 types of fluids (blood, phlegm, yellow bile, black bile).
• Camillo Golgi: Used a staining technique to illustrate neurons. Still believed the nervous system was continuous.

Neuron Doctrine

• Santiago Ramón y Cajal: Father of modern neuroscience.
• He discovered that the nervous system is composed of individual neurons separated by synapses.

Electrical and Chemical

• The nerve impulse, or action potential, is both electrical and chemical.
• Electrical transmission occurs within a neuron, while chemical transmission occurs between neurons at synapses. This process involves neurotransmitters.
• The action potential is the signal of information within a neuron, and neurotransmitters are the chemicals that carry the signal between neurons.

Glial Cells

• Glial cells support, protect, and insulate neurons.
• The blood-brain barrier, a critical function, is partly made up of glial cells
• Critical for neuron functioning.

Structure of a Neuron

• Neurons consist of cell bodies, axons, dendrites, myelin sheath, synapses, terminal buttons, and glial cells.
• Key structures of the neuron are the cell body (soma), dendrites, axon, myelin sheath, axon terminals, and the node of Ranvier

The Neuron

• The basic unit of the nervous system.
• Receives and transmits information.
• Information travels as an electrical signal within a neuron and as a chemical signal between neurons.

The Soma

• The cell body of the neuron.
• Contains the nucleus and other organelles.
• Receives signals from other neurons through dendrites.
• Generates the action potential.

The Axon

• A long projection extending from the soma.
• Transmits electrical signals (action potentials) away from the soma.
• Myelin sheath around the axon increases the speed of signal transmission.
• The axon terminal contains neurotransmitters.

The Terminal Button

• Knob at the end of an axon.
• Contains synaptic vesicles filled with neurotransmitters,
• Release of neurotransmitters into the synapse.

The Action Potential (Electrical Signal)

• A rapid change in the electrical potential of a neuron.
• Involves the movement of sodium and potassium ions across the neuronal membrane.
• Three phases: Resting potential, Depolarisation, Repolarization
  • Resting Potential: neuron is at its normal polarized state (-70mV)
  • Depolarisation: a shift towards a positive membrane potential (+40mV) caused by inflow of sodium ions
  • Repolarisation: return from positive to negative membrane potential (-70mV) caused by outward flow of potassium ions

The Node of Ranvier

• Gaps in the myelin sheath.
• Enable the rapid transmission of the action potential through saltatory conduction.
• Action potential "jumps" across the nodes.

Repolarization

• The process that restores the neuron to its resting potential (-70mV).
• Involves K+ ions flowing out of the neuron.

Neurotransmission

• The communication between neurons that involves neurotransmitters.
• Once the action potential reaches the terminal button, the electrical signal ends. The chemical signal begins
• Chemicals that transmit information between neurons.
• Synaptic vesicles release NTs into the synaptic cleft.

Neurotransmitters (NTs):

• Chemicals that carry signals across synapses.
• Different NTs have different effects on the receiving neuron.
• Neurotransmitters bind to receptor sites to influence a post-synaptic neuron

What Happens After Neurotransmitters are Released?

• Reuptake: Excess neurotransmitters are reabsorbed by the presynaptic neuron.
• Enzymatic degradation: Specialized enzymes break down the neurotransmitters.

Neurotransmitter Examples

• Glutamate, GABA, Acetylcholine, Dopamine, Serotonin, Epinephrine, Norepinephrine.

Glutamate and GABA

• Glutamate: principal excitatory neurotransmitter involved in learning & memory. Too much can cause seizures.
• GABA: major inhibitory neurotransmitter; slows down brain activity, crucial for regulating neural activity

Acetylcholine

• Controls muscle movement, learning & memory.
• Found at neuromuscular junctions.

Dopamine

• Released in response to rewarding behaviors; involved in voluntary motor control and addictive behavior

Serotonin

• Involved in sleep & dreaming; regulates emotional states; associated with depression.

Epinephrine and Norepinephrine

• Arousal and alertness.
• Associated with stress responses and rapid action; increases heart and breathing rate.

The Brain

• The control centre for the body.
• Consists of different sections with different functions

The Hindbrain

• Oldest part of the brain
• Includes the medulla, pons, and cerebellum.
• Regulates basic bodily functions (breathing, heart rate, blood pressure).
• Coordinates movement and balance.

The Midbrain

• The middle part of the brain
• Includes the reticular formation
• Important in sleep-wake cycles & arousal.

The Forebrain

• The biggest part of the brain.
• Includes the thalamus, hypothalamus, limbic system & cerebral cortex.
• Controls complex cognitive and emotional functions.

The Limbic System

• Important in regulating emotions, motivation, and memory.
• Includes structures like the hippocampus, amygdala, and hypothalamus.

Hippocampus

• A limbic structure essential for learning and memory.
• Important for converting short-term memories into long-term memories

Amygdala

• An almond-shaped structure involved in processing emotions, particularly fear

Cingulate Gyrus

• Involved in attention, cognitive control, and emotion.

Basal Ganglia

• Involved in motor control.
• Associated with conditions like Parkinson's disease.

The Changing Brain

• Neuroplasticity: The brain's ability to change and adapt throughout life by forming new connections based on experience and learning.
• Necessary for learning and memory.
• The brain does not waste any area or neuron, so it is very active and adaptive.

The Cerebral Cortex

• Responsible for higher-level functions.
• Divided into four lobes: Frontal, Parietal, Occipital, Temporal.
• The outer layer of the cerebrum.

The Cerebral Hemispheres

• Two halves of the brain.
• Some functions are predominantly located on one hemisphere.

Corpus Callosum and Insula

• Corpus Callosum: Nerve fibers connecting the two hemispheres.
• Insula: Involved in bodily sensations, emotions, and empathy.

Split Brain

• A surgical procedure that severs the corpus callosum.
• Demonstrates the lateralization of brain function.

The Motor Cortex

• Responsible for voluntary movements of skeletal muscles.

The Parietal Lobe

• Involved in processing sensory information.
• Perception of spatial relationships.

Hemispheric Neglect

• A condition where individuals fail to attend to one side of space.

The Somatosensory Cortex

• Sensory information from the body (pressure, temperature, pain)
• Processing of sensory information

The Occipital Lobe

• Visual cortex; responsible for processing visual information.
• Perception and interpretation of visual stimuli.

The Temporal Lobe

• Primarily auditory cortex, responsible for processing auditory information.
• Also involved in memory and language.

Aphasia

• Difficulty in understanding or producing language.
• Caused by damage to Broca's or Wernicke's areas.

Frontal Lobe

• Higher cognitive functions (planning, decision-making).
• Prefrontal cortex.
• Motor control

Phineas Gage

• A famous case study illustrating the importance of the frontal lobe in personality and behavior.